Martin Joel Erzinger, a financial advisor in Denver, Colorado, was accused of hitting Dr. Stephen Milo with his car on July 3 before driving away. He was caught a short time later in a parking lot across town.

"When you take a case through jury trial, there's always certainly a bit of uncertainty. This is a guarantee that he will have this on the record for the rest of his life," Mark Hurlbert told ABC News.

Hurlbert, who was also the prosecutor in the rape case that was dismissed against Kobe Bryant in September 2004, said the decision to drop the felony charge was not an act of leniency based on Erzinger's wealth or occupation. Instead, Hurlbert said, a felony charge through a jury trial was uncertain to be as punitive as two misdemeanor charges.

Erzinger, 52, now faces two misdemeanor traffic charges for leaving the scene of an accident and causing serious bodily injury.

"For the rest of his life, Mr. Erzinger will have on his record that he drove carelessly and caused serious bodily injury to another human being," said Hurlbert. "He may face potential jail time, which is up to a judge. And he'll lose his driver's license and pay restitution."

According to court records, Erzinger didn't call the police. When they tracked him down, he was placing his rearview mirror and a piece of the bumper in his trunk.

Milo, 34, who lives in New York City, suffered spinal cord injuries and bleeding from his brain.